Not to sound like a rogue agent here, and as an aside i agree in principal with almost everything that Dwhitt has to say, but i do offer up an different opinion when it comes to subs.
You can purchase two fine Velodyne subs for $150 each to cover the low end. There is a growing train of though that the sub frequencies can be equally well served by several smaller diaphragms than a single behemoth; after all at this freq. range it is primarily about moving air. If it is good enough for Nelson Pass it is probably good enough for me
